1) Take the lore and worldcrafting seriously again. this is the grand difference for me between Morrowind and Oblivion. Vvardenfell was an interesting, quirky, yet surprisingly believable world, with religious and political conflicts, history affecting the present. The imperial province was a bland medival fairy tale land without intrigue, without struggle. And that was the heart of the empire! The missed opportunity! Hire writing talent.

2) Go back to DF's character system (Disagree with Dhruin here, there is enough XP + level, systems, the use system may create its problems, but it also has its strengths. DF's was great).

3) Branching quests, permanent and significant consequences.

4) Factions that are at odds, presenting the player with clear dilemmas on who to side with